The Vampires can't hunt him now since it is still daytime. The wood elves on the other hand are already rallying. It will only be a matter of hours before more Origin gods are sent after him.
He has until nightfall to do something or the entire Underdark will become hostile to him. The Underdark is their home ground after all. The wood elves might not be able to enter the underdark easily but that is no consolation to him.
"There is no use waiting for death. If I am going to go down, then I'll bring everyone down with me."
He might die soon, but he will at least make sure to be a thorn in the neck of everyone on the plane. His plan doesn't need him to die. The danger to his life is when the plan fails. But he is willing to do it anyway and risk his life just to trouble everyone else.
